ATP‐dependent regulation of nuclear Ca2+ levels in plant cells

• Published in: FEBS letters Vol. 476; no. 3; pp. 145 - 149
• Main Authors: Bunney, Tom D., Shaw, Peter J., Watkins, Peter A.C., Taylor, J.Philip, Beven, Alison F., Wells, Brian, Calder, Grant M., Drøbak, Bjørn K.
• Format: Journal Article
• Language: English
• Published: 07-07-2000
• Subjects: [Ca2+]cyt, cytoplasmic Ca2+ concentration; [Ca2+]ext, extranuclear Ca2+ concentration; [Ca2+]nuc, intranuclear Ca2+ concentration; Ca2+ uptake; Imaging; Nuclear pore complex; Nucleus; Plant; Signal transduction
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(00)01709-9

Localised alterations in cytoplasmic Ca2+ levels are an integral part of the response of eukaryotic cells to a plethora of external stimuli. Due to the large size of nuclear pores, it has generally been assumed that intranuclear Ca2+ levels reflect the prevailing cytoplasmic Ca2+ levels. Using nuclei prepared from carrot (Daucus carota L.) cells, we now show that Ca2+ can be transported across nuclear membranes in an ATP‐dependent manner and that over 95% of Ca2+ is accumulated into a pool releasable by the Ca2+ ionophore A.23187. ATP‐dependent nuclear Ca2+ uptake did not occur in the presence of ADP or ADPγS and was abolished by orthovanadate. Confocal microscopy of nuclei loaded with dextran‐linked Indo‐1 showed that the initial ATP‐induced rise in [Ca2+] occurs in the nuclear periphery. The occurrence of ATP‐dependent Ca2+ uptake in plant nuclei suggests that alterations of intranuclear Ca2+ levels may occur independently of cytoplasmic [Ca2+] changes.